Polar bears rely on sea ice for food - hunting seal pups in particular - but a new paper published in the PLOS-ONE science journal claims polar bears could survive on land-based food.

Scientists at the AMNH believe the animals have dietary flexibility with researcher Robert Rockwell saying the bears are opportunists.

"[Polar bears] have been documented consuming various types and combinations of land-based food since the earliest natural history records," Dr Rockwell said.

Dr Rockwell and Linda Gormezano found prey such as caribou, snow geese and snow goose eggs could provide more calories than the bears would burn hunting them.

"Our results suggest that the net energy from land-based food, after subtracting costs of limited movement to obtain it, could eliminate all projected nutritional deficits of starving adult male polar bears and likely other demographic groups as well," they wrote.